What is Smog? 10 States in India with Deadliest Smog

Smog is a type of air pollution characterized by a mixture of smoke and fog, thereby reducing visibility and affecting health. The word “smog” is derived from the merging of “smoke” and “fog” and was used in the early 20th century to refer to atmospheric conditions in industrial cities, especially when it was foggy in the colder months.

Types of smog

There are two main types of smoke:

Photochemical smog: Formed when the sun interacts with nitrogen oxides and volatile organic compounds in the atmosphere. It produces ground-level ozone as well as other air toxins. It is more common in areas with large-scale urbanization and high levels of transportation and industrialization.

Sulfur Smog: Often referred to as “London Smog,” this smog is caused by high concentrations of sulfur oxides produced by the burning of fossil fuels such as coal. It usually occurs during colder periods when humidity is higher.

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health effects

Smoke has serious health effects, including:

  • Respiratory problems, such as coughing and wheezing
  • Eye and throat irritation
  • Severe cases of cardiovascular disease and lung disease
  • For people who already suffer from conditions such as asthma, the reaction is extremely sensitive.

India’s most smoggy state

Severe haze weather in the country mainly occurs in winter. Causes of these problems include straw burning, vehicle emissions and industrial pollution. The states with the worst smog in India are:

  • Delhi: Delhi has long been considered one of the most polluted cities in the world, with PM2.5 levels often well above safe limits.
  • Punjab: Agricultural practices, especially stubble burning, significantly contribute to air pollution in Delhi and other adjoining areas.
  • Haryana: Like Punjab, this state is also heavily polluted by agricultural fires4.
  • Uttar Pradesh: Industrialization and urbanization have created huge problems for air quality.
  • Maharashtra: Vehicle exhaust and industrial wastewater emissions are major pollutants in cities like Mumbai.
  • Rajasthan: Dust storms and industrial wastewater deposits are harming air quality.
  • Gujarat: The industrially developed state of Gujarat has serious air pollution.
  • West Bengal: In Kolkata, severe air pollution is mainly caused by vehicle emissions and construction dust.
  • Tamil Nadu: Chennai city faces challenge of industrial pollution.
  • Bihar: Rapid urbanization has led to worsening air quality in cities like Patna.

As of November 18, 2024, the air quality index (AQI) has reached alarming levels in various states in India, especially in the northern regions. The following is a summary of AQI data for major states affected by severe haze that day:

rank

state

City

air quality index

Air Quality Index Category

prominent pollutants

1

delhi

delhi

978

dangerous

PM2.5

2

Haryana

Gurugram

Chapter 631

Very bad

PM2.5

3

uttar pradesh

Ghaziabad

600

Very bad

PM2.5

4

punjab province

amritsar

Chapter 580

Very bad

PM2.5

5

bihar

patna

550

Very bad

PM2.5

6

rajasthan

jaipur

520

Very bad

PM2.5

7

Uttarakhand

dehradun

510

Very bad

PM2.5

8

Chandigarh

Chandigarh

Chapter 485

Very bad

PM2.5

9

himachal pradesh

Shimla

Chapter 470

Very bad

PM2.5

10

west bengal

calcutta

450

poor

PM2.5

Key observations

  • Delhi’s highest air quality index was 978, which falls into the hazardous category, indicating severe health risks for all residents.
  • Haryana and Uttar Pradesh also experienced extremely poor air quality, with AQI values ​​of 631 and 600 respectively.
  • Other states like Punjab and Bihar are also facing severe air quality issues with high levels of PM2.5 posing health hazards.

These states experience seasonal peaks in smog concentrations from October to January as weather conditions trap pollutants near the ground, increasing health risks to local residents.

Also Read | Delhi Air Pollution: What pollutes Delhi’s air and what are the major contributors in the capital NCR? What is GRAP Phase 4? View its full table and content on controlling pollution in the National Capital Region of Delhi